| 1 | /* |
| 2 | * Copyright 2006-2010 the original author or authors. |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package org.springframework.batch.item.database; |
| 17 | |
| 18 | import java.util.Collection; |
| 19 | import java.util.List; |
| 20 | import java.util.Map; |
| 21 | |
| 22 | import org.hibernate.Query; |
| 23 | import org.hibernate.ScrollMode; |
| 24 | import org.hibernate.ScrollableResults; |
| 25 | import org.hibernate.Session; |
| 26 | import org.hibernate.SessionFactory; |
| 27 | import org.hibernate.StatelessSession; |
| 28 | import org.springframework.batch.item.database.orm.HibernateQueryProvider; |
| 29 | import org.springframework.beans.factory.InitializingBean; |
| 30 | import org.springframework.util.Assert; |
| 31 | import org.springframework.util.StringUtils; |
| 32 | |
| 33 | /** |
| 34 | * Internal shared state helper for hibernate readers managing sessions and |
| 35 | * queries. |
| 36 | * |
| 37 | * @author Dave Syer |
| 38 | * |
| 39 | */ |
| 40 | public class HibernateItemReaderHelper<T> implements InitializingBean { |
| 41 | |
| 42 | private SessionFactory sessionFactory; |
| 43 | |
| 44 | private String queryString = ""; |
| 45 | |
| 46 | private String queryName = ""; |
| 47 | |
| 48 | private HibernateQueryProvider queryProvider; |
| 49 | |
| 50 | private boolean useStatelessSession = true; |
| 51 | |
| 52 | private StatelessSession statelessSession; |
| 53 | |
| 54 | private Session statefulSession; |
| 55 | |
| 56 | /** |
| 57 | * @param queryName name of a hibernate named query |
| 58 | */ |
| 59 | public void setQueryName(String queryName) { |
| 60 | this.queryName = queryName; |
| 61 | } |
| 62 | |
| 63 | /** |
| 64 | * @param queryString HQL query string |
| 65 | */ |
| 66 | public void setQueryString(String queryString) { |
| 67 | this.queryString = queryString; |
| 68 | } |
| 69 | |
| 70 | /** |
| 71 | * @param queryProvider Hibernate query provider |
| 72 | */ |
| 73 | public void setQueryProvider(HibernateQueryProvider queryProvider) { |
| 74 | this.queryProvider = queryProvider; |
| 75 | } |
| 76 | |
| 77 | /** |
| 78 | * Can be set only in uninitialized state. |
| 79 | * |
| 80 | * @param useStatelessSession <code>true</code> to use |
| 81 | * {@link StatelessSession} <code>false</code> to use standard hibernate |
| 82 | * {@link Session} |
| 83 | */ |
| 84 | public void setUseStatelessSession(boolean useStatelessSession) { |
| 85 | Assert.state(statefulSession == null && statelessSession == null, |
| 86 | "The useStatelessSession flag can only be set before a session is initialized."); |
| 87 | this.useStatelessSession = useStatelessSession; |
| 88 | } |
| 89 | |
| 90 | /** |
| 91 | * @param sessionFactory hibernate session factory |
| 92 | */ |
| 93 | public void setSessionFactory(SessionFactory sessionFactory) { |
| 94 | this.sessionFactory = sessionFactory; |
| 95 | } |
| 96 | |
| 97 | public void afterPropertiesSet() throws Exception { |
| 98 | |
| 99 | Assert.state(sessionFactory != null, "A SessionFactory must be provided"); |
| 100 | |
| 101 | if (queryProvider == null) { |
| 102 | Assert.notNull(sessionFactory, "session factory must be set"); |
| 103 | Assert.state(StringUtils.hasText(queryString) ^ StringUtils.hasText(queryName), |
| 104 | "queryString or queryName must be set"); |
| 105 | } |
| 106 | // making sure that the appropriate (Hibernate) query provider is set |
| 107 | else { |
| 108 | Assert.state(queryProvider != null, "Hibernate query provider must be set"); |
| 109 | } |
| 110 | |
| 111 | } |
| 112 | |
| 113 | /** |
| 114 | * Get a cursor over all of the results, with the forward-only flag set. |
| 115 | * |
| 116 | * @param fetchSize the fetch size to use retrieving the results |
| 117 | * @param parameterValues the parameter values to use (or null if none). |
| 118 | * |
| 119 | * @return a forward-only {@link ScrollableResults} |
| 120 | */ |
| 121 | public ScrollableResults getForwardOnlyCursor(int fetchSize, Map<String, Object> parameterValues) { |
| 122 | Query query = createQuery(); |
| 123 | if (parameterValues != null) { |
| 124 | query.setProperties(parameterValues); |
| 125 | } |
| 126 | return query.setFetchSize(fetchSize).scroll(ScrollMode.FORWARD_ONLY); |
| 127 | } |
| 128 | |
| 129 | /** |
| 130 | * Open appropriate type of hibernate session and create the query. |
| 131 | */ |
| 132 | public Query createQuery() { |
| 133 | |
| 134 | if (useStatelessSession) { |
| 135 | if (statelessSession == null) { |
| 136 | statelessSession = sessionFactory.openStatelessSession(); |
| 137 | } |
| 138 | if (queryProvider != null) { |
| 139 | queryProvider.setStatelessSession(statelessSession); |
| 140 | } |
| 141 | else { |
| 142 | if (StringUtils.hasText(queryName)) { |
| 143 | return statelessSession.getNamedQuery(queryName); |
| 144 | } |
| 145 | else { |
| 146 | return statelessSession.createQuery(queryString); |
| 147 | } |
| 148 | } |
| 149 | } |
| 150 | else { |
| 151 | if (statefulSession == null) { |
| 152 | statefulSession = sessionFactory.openSession(); |
| 153 | } |
| 154 | if (queryProvider != null) { |
| 155 | queryProvider.setSession(statefulSession); |
| 156 | } |
| 157 | else { |
| 158 | if (StringUtils.hasText(queryName)) { |
| 159 | return statefulSession.getNamedQuery(queryName); |
| 160 | } |
| 161 | else { |
| 162 | return statefulSession.createQuery(queryString); |
| 163 | } |
| 164 | } |
| 165 | } |
| 166 | |
| 167 | // If queryProvider is set use it to create a query |
| 168 | return queryProvider.createQuery(); |
| 169 | |
| 170 | } |
| 171 | |
| 172 | /** |
| 173 | * Scroll through the results up to the item specified. |
| 174 | * |
| 175 | * @param cursor the results to scroll over |
| 176 | */ |
| 177 | public void jumpToItem(ScrollableResults cursor, int itemIndex, int flushInterval) { |
| 178 | for (int i = 0; i < itemIndex; i++) { |
| 179 | cursor.next(); |
| 180 | if (i % flushInterval == 0 && !useStatelessSession) { |
| 181 | statefulSession.clear(); // Clears in-memory cache |
| 182 | } |
| 183 | } |
| 184 | } |
| 185 | |
| 186 | /** |
| 187 | * Close the open session (stateful or otherwise). |
| 188 | */ |
| 189 | public void close() { |
| 190 | if (statelessSession != null) { |
| 191 | statelessSession.close(); |
| 192 | statelessSession = null; |
| 193 | } |
| 194 | if (statefulSession != null) { |
| 195 | statefulSession.close(); |
| 196 | statefulSession = null; |
| 197 | } |
| 198 | } |
| 199 | |
| 200 | /** |
| 201 | * Read a page of data, clearing the existing session (if necessary) first, |
| 202 | * and creating a new session before executing the query. |
| 203 | * |
| 204 | * @param page the page to read (starting at 0) |
| 205 | * @param pageSize the size of the page or maximum number of items to read |
| 206 | * @param fetchSize the fetch size to use |
| 207 | * @param parameterValues the parameter values to use (if any, otherwise |
| 208 | * null) |
| 209 | * @return a collection of items |
| 210 | */ |
| 211 | public Collection<? extends T> readPage(int page, int pageSize, int fetchSize, Map<String, Object> parameterValues) { |
| 212 | |
| 213 | clear(); |
| 214 | |
| 215 | Query query = createQuery(); |
| 216 | if (parameterValues != null) { |
| 217 | query.setProperties(parameterValues); |
| 218 | } |
| 219 | @SuppressWarnings("unchecked") |
| 220 | List<T> result = query.setFetchSize(fetchSize).setFirstResult(page * pageSize).setMaxResults(pageSize).list(); |
| 221 | return result; |
| 222 | |
| 223 | } |
| 224 | |
| 225 | /** |
| 226 | * Clear the session if stateful. |
| 227 | */ |
| 228 | public void clear() { |
| 229 | if (statefulSession != null) { |
| 230 | statefulSession.clear(); |
| 231 | } |
| 232 | } |
| 233 | |
| 234 | } |